The firm says it was induced to work for Leichtenstein based Quatif Finance Establishment after Christopher Stephenson claimed it was owned by the royal family of Brunei, whose sultan is Hassanal Bolkiah.

Ernst & Young carried out more than £100,000 worth of work but despite requests both Quatif and Stephenson have failed to pay a penny, according to a High Court writ.

Now the accountants are suing Quatif for £106,867.64, and claiming damages of more than £100,000 from Stephenson, who lives in Monte Carlo.

If the firm had known that Quatif was unconnected with Brunei, it would not have entered into the agreement because of Quatif’s location, and concerns over payment, it is alleged. Stephenson knew who the true owners of Quatif were and if he did not know, he should not have claimed that he did, the writ says.

Ernst and Young had carried out a market assessment and financial due diligence over a proposed acquisition of Wentworth Group Holdings in 1998.

The firm sent bills for £20,000 and £50,000 in December 1998, but Quatif failed to pay any money. A year later, Quatif wrote refusing to pay the invoices, and wrongfully claimed that no money was owed, the writ claims.